blob: 88f140d750fad53c9238fb86e6f1c698e779d49e [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Defines the public interface of the disk cache. For more details see
// http://dev.chromium.org/developers/design-documents/network-stack/disk-cache
#ifndef NET_DISK_CACHE_DISK_CACHE_H_
#define NET_DISK_CACHE_DISK_CACHE_H_
#include <stdint.h>
#include <memory>
#include <string>
#include <vector>
#include "base/files/file.h"
#include "base/memory/ref_counted.h"
#include "base/strings/string_split.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "net/base/cache_type.h"
#include "net/base/completion_once_callback.h"
#include "net/base/net_errors.h"
#include "net/base/net_export.h"
#include "net/base/request_priority.h"
#include "third_party/abseil-cpp/absl/types/optional.h"
namespace base {
class FilePath;
namespace android {
class ApplicationStatusListener;
} // namespace android
} // namespace base
namespace net {
class IOBuffer;
class NetLog;
}
namespace disk_cache {
class Entry;
class Backend;
class EntryResult;
class BackendFileOperationsFactory;
struct RangeResult;
using EntryResultCallback = base::OnceCallback<void(EntryResult)>;
using RangeResultCallback = base::OnceCallback<void(const RangeResult&)>;
// How to handle resetting the back-end cache from the previous session.
// See CreateCacheBackend() for its usage.
enum class ResetHandling { kReset, kResetOnError, kNeverReset };
// Returns an instance of a Backend of the given `type`. `file_operations`
// (nullable) is used to broker file operations in sandboxed environments.
// Currently `file_operations` is only used for the simple backend.
// `path` points to a folder where the cached data will be stored (if
// appropriate). This cache instance must be the only object that will be
// reading or writing files to that folder (if another one exists, and `type` is
// not net::DISK_CACHE this operation will not complete until the previous
// duplicate gets destroyed and finishes all I/O). The returned object should be
// deleted when not needed anymore.
//
// If `reset_handling` is set to kResetOnError and there is a problem with the
// cache initialization, the files will be deleted and a new set will be
// created. If it's set to kReset, this will happen even if there isn't a
// problem with cache initialization. Finally, if it's set to kNeverReset, the
// cache creation will fail if there is a problem with cache initialization.
//
// `max_bytes` is the maximum size the cache can grow to. If zero is passed in
// as `max_bytes`, the cache will determine the value to use. The returned
// pointer can be nullptr if a fatal error is found. The actual return value of
// the function is a net error code. If this function returns ERR_IO_PENDING,
// the `callback` will be invoked when a backend is available or a fatal error
// condition is reached. The pointer to receive the `backend` must remain valid
// until the operation completes (the callback is notified).
NET_EXPORT net::Error CreateCacheBackend(
net::CacheType type,
net::BackendType backend_type,
scoped_refptr<BackendFileOperationsFactory> file_operations,
const base::FilePath& path,
int64_t max_bytes,
ResetHandling reset_handling,
net::NetLog* net_log,
std::unique_ptr<Backend>* backend,
net::CompletionOnceCallback callback);
#if BUILDFLAG(IS_ANDROID)
// Similar to the function above, but takes an |app_status_listener| which is
// used to listen for when the Android application status changes, so we can
// flush the cache to disk when the app goes to the background.
NET_EXPORT net::Error CreateCacheBackend(
net::CacheType type,
net::BackendType backend_type,
scoped_refptr<BackendFileOperationsFactory> file_operations,
const base::FilePath& path,
int64_t max_bytes,
ResetHandling reset_handling,
net::NetLog* net_log,
std::unique_ptr<Backend>* backend,
net::CompletionOnceCallback callback,
base::android::ApplicationStatusListener* app_status_listener);
#endif
// Variant of the above that calls |post_cleanup_callback| once all the I/O
// that was in flight has completed post-destruction. |post_cleanup_callback|
// will get invoked even if the creation fails. The invocation will always be
// via the event loop, and never direct.
//
// This is currently unsupported for |type| == net::DISK_CACHE.
//
// Note that this will not wait for |post_cleanup_callback| of a previous
// instance for |path| to run.
NET_EXPORT net::Error CreateCacheBackend(
net::CacheType type,
net::BackendType backend_type,
scoped_refptr<BackendFileOperationsFactory> file_operations,
const base::FilePath& path,
int64_t max_bytes,
ResetHandling reset_handling,
net::NetLog* net_log,
std::unique_ptr<Backend>* backend,
base::OnceClosure post_cleanup_callback,
net::CompletionOnceCallback callback);
// This will flush any internal threads used by backends created w/o an
// externally injected thread specified, so tests can be sure that all I/O
// has finished before inspecting the world.
NET_EXPORT void FlushCacheThreadForTesting();
// Async version of FlushCacheThreadForTesting. `callback` will be called on
// the calling sequence.
NET_EXPORT void FlushCacheThreadAsynchronouslyForTesting(
base::OnceClosure cllback);
// The root interface for a disk cache instance.
class NET_EXPORT Backend {
public:
using CompletionOnceCallback = net::CompletionOnceCallback;
using Int64CompletionOnceCallback = net::Int64CompletionOnceCallback;
using EntryResultCallback = disk_cache::EntryResultCallback;
using EntryResult = disk_cache::EntryResult;
class Iterator {
public:
virtual ~Iterator() {}
// OpenNextEntry returns a result with net_error() |net::OK| and provided
// entry if there is an entry to enumerate which it can return immediately.
// It returns a result with net_error() |net::ERR_FAILED| at the end of
// enumeration. If the function returns a result with net_error()
// |net::ERR_IO_PENDING|, then the final result will be passed to the
// provided |callback|, otherwise |callback| will not be called. If any
// entry in the cache is modified during iteration, the result of this
// function is thereafter undefined.
//
// Calling OpenNextEntry after the backend which created it is destroyed
// may fail with |net::ERR_FAILED|; however it should not crash.
//
// Some cache backends make stronger guarantees about mutation during
// iteration, see top comment in simple_backend_impl.h for details.
virtual EntryResult OpenNextEntry(EntryResultCallback callback) = 0;
};
// If the backend is destroyed when there are operations in progress (any
// callback that has not been invoked yet), this method cancels said
// operations so the callbacks are not invoked, possibly leaving the work
// half way (for instance, dooming just a few entries). Note that pending IO
// for a given Entry (as opposed to the Backend) will still generate a
// callback.
// Warning: there is some inconsistency in details between different backends
// on what will succeed and what will fail. In particular the blockfile
// backend will leak entries closed after backend deletion, while others
// handle it properly.
Backend(net::CacheType cache_type) : cache_type_(cache_type) {}
virtual ~Backend() {}
// Returns the type of this cache.
net::CacheType GetCacheType() const { return cache_type_; }
// Returns the number of entries in the cache.
virtual int32_t GetEntryCount() const = 0;
// Atomically attempts to open an existing entry based on |key| or, if none
// already exists, to create a new entry. Returns an EntryResult object,
// which contains 1) network error code; 2) if the error code is OK,
// an owning pointer to either a preexisting or a newly created
// entry; 3) a bool indicating if the entry was opened or not. When the entry
// pointer is no longer needed, its Close() method should be called. If this
// method return value has net_error() == ERR_IO_PENDING, the
// |callback| will be invoked when the entry is available. The |priority| of
// the entry determines its priority in the background worker pools.
//
// This method should be the preferred way to obtain an entry over using
// OpenEntry() or CreateEntry() separately in order to simplify consumer
// logic.
virtual EntryResult OpenOrCreateEntry(const std::string& key,
net::RequestPriority priority,
EntryResultCallback callback) = 0;
// Opens an existing entry, returning status code, and, if successful, an
// entry pointer packaged up into an EntryResult. If return value's
// net_error() is ERR_IO_PENDING, the |callback| will be invoked when the
// entry is available. The |priority| of the entry determines its priority in
// the background worker pools.
virtual EntryResult OpenEntry(const std::string& key,
net::RequestPriority priority,
EntryResultCallback) = 0;
// Creates a new entry, returning status code, and, if successful, and
// an entry pointer packaged up into an EntryResult. If return value's
// net_error() is ERR_IO_PENDING, the |callback| will be invoked when the
// entry is available. The |priority| of the entry determines its priority in
// the background worker pools.
virtual EntryResult CreateEntry(const std::string& key,
net::RequestPriority priority,
EntryResultCallback callback) = 0;
// Marks the entry, specified by the given key, for deletion. The return value
// is a net error code. If this method returns ERR_IO_PENDING, the |callback|
// will be invoked after the entry is doomed.
virtual net::Error DoomEntry(const std::string& key,
net::RequestPriority priority,
CompletionOnceCallback callback) = 0;
// Marks all entries for deletion. The return value is a net error code. If
// this method returns ERR_IO_PENDING, the |callback| will be invoked when the
// operation completes.
virtual net::Error DoomAllEntries(CompletionOnceCallback callback) = 0;
// Marks a range of entries for deletion. This supports unbounded deletes in
// either direction by using null Time values for either argument. The return
// value is a net error code. If this method returns ERR_IO_PENDING, the
// |callback| will be invoked when the operation completes.
// Entries with |initial_time| <= access time < |end_time| are deleted.
virtual net::Error DoomEntriesBetween(base::Time initial_time,
base::Time end_time,
CompletionOnceCallback callback) = 0;
// Marks all entries accessed since |initial_time| for deletion. The return
// value is a net error code. If this method returns ERR_IO_PENDING, the
// |callback| will be invoked when the operation completes.
// Entries with |initial_time| <= access time are deleted.
virtual net::Error DoomEntriesSince(base::Time initial_time,
CompletionOnceCallback callback) = 0;
// Calculate the total size of the cache. The return value is the size in
// bytes or a net error code. If this method returns ERR_IO_PENDING,
// the |callback| will be invoked when the operation completes.
virtual int64_t CalculateSizeOfAllEntries(
Int64CompletionOnceCallback callback) = 0;
// Calculate the size of all cache entries accessed between |initial_time| and
// |end_time|.
// The return value is the size in bytes or a net error code. The default
// implementation returns ERR_NOT_IMPLEMENTED and should only be overwritten
// if there is an efficient way for the backend to determine the size for a
// subset of the cache without reading the whole cache from disk.
// If this method returns ERR_IO_PENDING, the |callback| will be invoked when
// the operation completes.
virtual int64_t CalculateSizeOfEntriesBetween(
base::Time initial_time,
base::Time end_time,
Int64CompletionOnceCallback callback);
// Returns an iterator which will enumerate all entries of the cache in an
// undefined order.
virtual std::unique_ptr<Iterator> CreateIterator() = 0;
// Return a list of cache statistics.
virtual void GetStats(base::StringPairs* stats) = 0;
// Called whenever an external cache in the system reuses the resource
// referred to by |key|.
virtual void OnExternalCacheHit(const std::string& key) = 0;
// Backends can optionally permit one to store, probabilistically, up to a
// byte associated with a key of an existing entry in memory.
// GetEntryInMemoryData has the following behavior:
// - If the data is not available at this time for any reason, returns 0.
// - Otherwise, returns a value that was with very high probability
// given to SetEntryInMemoryData(|key|) (and with a very low probability
// to a different key that collides in the in-memory index).
//
// Due to the probability of collisions, including those that can be induced
// by hostile 3rd parties, this interface should not be used to make decisions
// that affect correctness (especially security).
virtual uint8_t GetEntryInMemoryData(const std::string& key);
virtual void SetEntryInMemoryData(const std::string& key, uint8_t data);
// Returns the maximum length an individual stream can have.
virtual int64_t MaxFileSize() const = 0;
private:
const net::CacheType cache_type_;
};
// This interface represents an entry in the disk cache.
class NET_EXPORT Entry {
public:
using CompletionOnceCallback = net::CompletionOnceCallback;
using IOBuffer = net::IOBuffer;
using RangeResultCallback = disk_cache::RangeResultCallback;
using RangeResult = disk_cache::RangeResult;
// Marks this cache entry for deletion.
virtual void Doom() = 0;
// Releases this entry. Calling this method does not cancel pending IO
// operations on this entry. Even after the last reference to this object has
// been released, pending completion callbacks may be invoked.
virtual void Close() = 0;
// Returns the key associated with this cache entry.
virtual std::string GetKey() const = 0;
// Returns the time when this cache entry was last used.
virtual base::Time GetLastUsed() const = 0;
// Returns the time when this cache entry was last modified.
virtual base::Time GetLastModified() const = 0;
// Returns the size of the cache data with the given index.
virtual int32_t GetDataSize(int index) const = 0;
// Copies cached data into the given buffer of length |buf_len|. Returns the
// number of bytes read or a network error code. If this function returns
// ERR_IO_PENDING, the completion callback will be called on the current
// thread when the operation completes, and a reference to |buf| will be
// retained until the callback is called. Note that as long as the function
// does not complete immediately, the callback will always be invoked, even
// after Close has been called; in other words, the caller may close this
// entry without having to wait for all the callbacks, and still rely on the
// cleanup performed from the callback code.
virtual int ReadData(int index,
int offset,
IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback) = 0;
// Copies data from the given buffer of length |buf_len| into the cache.
// Returns the number of bytes written or a network error code. If this
// function returns ERR_IO_PENDING, the completion callback will be called
// on the current thread when the operation completes, and a reference to
// |buf| will be retained until the callback is called. Note that as long as
// the function does not complete immediately, the callback will always be
// invoked, even after Close has been called; in other words, the caller may
// close this entry without having to wait for all the callbacks, and still
// rely on the cleanup performed from the callback code.
// If truncate is true, this call will truncate the stored data at the end of
// what we are writing here.
virtual int WriteData(int index,
int offset,
IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback,
bool truncate) = 0;
// Sparse entries support:
//
// A Backend implementation can support sparse entries, so the cache keeps
// track of which parts of the entry have been written before. The backend
// will never return data that was not written previously, so reading from
// such region will return 0 bytes read (or actually the number of bytes read
// before reaching that region).
//
// There are only two streams for sparse entries: a regular control stream
// (index 0) that must be accessed through the regular API (ReadData and
// WriteData), and one sparse stream that must me accessed through the sparse-
// aware API that follows. Calling a non-sparse aware method with an index
// argument other than 0 is a mistake that results in implementation specific
// behavior. Using a sparse-aware method with an entry that was not stored
// using the same API, or with a backend that doesn't support sparse entries
// will return ERR_CACHE_OPERATION_NOT_SUPPORTED.
//
// The storage granularity of the implementation should be at least 1 KB. In
// other words, storing less than 1 KB may result in an implementation
// dropping the data completely, and writing at offsets not aligned with 1 KB,
// or with lengths not a multiple of 1 KB may result in the first or last part
// of the data being discarded. However, two consecutive writes should not
// result in a hole in between the two parts as long as they are sequential
// (the second one starts where the first one ended), and there is no other
// write between them.
//
// The Backend implementation is free to evict any range from the cache at any
// moment, so in practice, the previously stated granularity of 1 KB is not
// as bad as it sounds.
//
// The sparse methods don't support multiple simultaneous IO operations to the
// same physical entry, so in practice a single object should be instantiated
// for a given key at any given time. Once an operation has been issued, the
// caller should wait until it completes before starting another one. This
// requirement includes the case when an entry is closed while some operation
// is in progress and another object is instantiated; any IO operation will
// fail while the previous operation is still in-flight. In order to deal with
// this requirement, the caller could either wait until the operation
// completes before closing the entry, or call CancelSparseIO() before closing
// the entry, and call ReadyForSparseIO() on the new entry and wait for the
// callback before issuing new operations.
// Behaves like ReadData() except that this method is used to access sparse
// entries.
virtual int ReadSparseData(int64_t offset,
IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback) = 0;
// Behaves like WriteData() except that this method is used to access sparse
// entries. |truncate| is not part of this interface because a sparse entry
// is not expected to be reused with new data. To delete the old data and
// start again, or to reduce the total size of the stream data (which implies
// that the content has changed), the whole entry should be doomed and
// re-created.
virtual int WriteSparseData(int64_t offset,
IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback) = 0;
// Returns information about the currently stored portion of a sparse entry.
// |offset| and |len| describe a particular range that should be scanned to
// find out if it is stored or not. Please see the documentation of
// RangeResult for more details.
virtual RangeResult GetAvailableRange(int64_t offset,
int len,
RangeResultCallback callback) = 0;
// Returns true if this entry could be a sparse entry or false otherwise. This
// is a quick test that may return true even if the entry is not really
// sparse. This method doesn't modify the state of this entry (it will not
// create sparse tracking data). GetAvailableRange or ReadSparseData can be
// used to perform a definitive test of whether an existing entry is sparse or
// not, but that method may modify the current state of the entry (making it
// sparse, for instance). The purpose of this method is to test an existing
// entry, but without generating actual IO to perform a thorough check.
virtual bool CouldBeSparse() const = 0;
// Cancels any pending sparse IO operation (if any). The completion callback
// of the operation in question will still be called when the operation
// finishes, but the operation will finish sooner when this method is used.
virtual void CancelSparseIO() = 0;
// Returns OK if this entry can be used immediately. If that is not the
// case, returns ERR_IO_PENDING and invokes the provided callback when this
// entry is ready to use. This method always returns OK for non-sparse
// entries, and returns ERR_IO_PENDING when a previous operation was cancelled
// (by calling CancelSparseIO), but the cache is still busy with it. If there
// is a pending operation that has not been cancelled, this method will return
// OK although another IO operation cannot be issued at this time; in this
// case the caller should just wait for the regular callback to be invoked
// instead of using this method to provide another callback.
//
// Note that CancelSparseIO may have been called on another instance of this
// object that refers to the same physical disk entry.
// Note: This method is deprecated.
virtual net::Error ReadyForSparseIO(CompletionOnceCallback callback) = 0;
// Used in tests to set the last used time. Note that backend might have
// limited precision. Also note that this call may modify the last modified
// time.
virtual void SetLastUsedTimeForTest(base::Time time) = 0;
protected:
virtual ~Entry() {}
};
struct EntryDeleter {
void operator()(Entry* entry) {
// Note that |entry| is ref-counted.
entry->Close();
}
};
// Automatically closes an entry when it goes out of scope.
// Warning: Be careful. Automatically closing may not be the desired behavior
// when writing to an entry. You may wish to doom first (e.g., in case writing
// hasn't yet completed but the browser is shutting down).
typedef std::unique_ptr<Entry, EntryDeleter> ScopedEntryPtr;
// Represents the result of an entry open or create operation.
// This is a move-only, owning type, which will close the entry it owns unless
// it's released from it via ReleaseEntry (or it's moved away from).
class NET_EXPORT EntryResult {
public:
EntryResult();
~EntryResult();
EntryResult(EntryResult&&);
EntryResult& operator=(EntryResult&&);
EntryResult(const EntryResult&) = delete;
EntryResult& operator=(const EntryResult&) = delete;
// Creates an entry result representing successfully opened (pre-existing)
// cache entry. |new_entry| must be non-null.
static EntryResult MakeOpened(Entry* new_entry);
// Creates an entry result representing successfully created (new)
// cache entry. |new_entry| must be non-null.
static EntryResult MakeCreated(Entry* new_entry);
// Creates an entry result representing an error. Status must not be net::OK.
static EntryResult MakeError(net::Error status);
// Relinquishes ownership of the entry, and returns a pointer to it.
// Will return nullptr if there is no such entry.
// WARNING: clears net_error() to ERR_FAILED, opened() to false.
Entry* ReleaseEntry();
// ReleaseEntry() will return a non-null pointer if and only if this is
// net::OK before the call to it.
net::Error net_error() const { return net_error_; }
// Returns true if an existing entry was opened rather than a new one created.
// Implies net_error() == net::OK and non-null entry.
bool opened() const { return opened_; }
private:
// Invariant to keep: |entry_| != nullptr iff |net_error_| == net::OK;
// |opened_| set only if entry is set.
net::Error net_error_ = net::ERR_FAILED;
bool opened_ = false;
ScopedEntryPtr entry_;
};
// Represents a result of GetAvailableRange.
struct NET_EXPORT RangeResult {
RangeResult() = default;
explicit RangeResult(net::Error error) : net_error(error) {}
RangeResult(int64_t start, int available_len)
: net_error(net::OK), start(start), available_len(available_len) {}
// This is net::OK if operation succeeded, and `start` and `available_len`
// were set appropriately (potentially with 0 for `available_len`).
//
// In return value of GetAvailableRange(), net::ERR_IO_PENDING means that the
// result will be provided asynchronously via the callback. This can not occur
// in the value passed to the callback itself.
//
// In case the operation failed, this will be the error code.
net::Error net_error = net::ERR_FAILED;
// First byte within the range passed to GetAvailableRange that's available
// in the cache entry.
//
// Valid iff net_error is net::OK.
int64_t start = -1;
// Number of consecutive bytes stored within the requested range starting from
// `start` that can be read at once. This may be zero.
//
// Valid iff net_error is net::OK.
int available_len = 0;
};
// The maximum size of cache that can be created for type
// GENERATED_WEBUI_BYTE_CODE_CACHE. There are only a handful of commonly
// accessed WebUI pages, which can each cache 0.5 - 1.5 MB of code. There is no
// point in having a very large WebUI code cache, even if lots of disk space is
// available.
constexpr int kMaxWebUICodeCacheSize = 5 * 1024 * 1024;
class UnboundBackendFileOperations;
// An interface to provide file operations so that the HTTP cache works on
// a sandboxed process.
// All the paths must be absolute paths.
// A BackendFileOperations object is bound to a sequence.
class BackendFileOperations {
public:
struct FileEnumerationEntry {
FileEnumerationEntry() = default;
FileEnumerationEntry(base::FilePath path,
int64_t size,
base::Time last_accessed,
base::Time last_modified)
: path(std::move(path)),
size(size),
last_accessed(last_accessed),
last_modified(last_modified) {}
base::FilePath path;
int64_t size = 0;
base::Time last_accessed;
base::Time last_modified;
};
// An enum representing the mode for DeleteFile function.
enum class DeleteFileMode {
// The default mode, meaning base::DeleteFile.
kDefault,
// Ensure that new files for the same name can be created immediately after
// deletion. Note that this is the default behavior on POSIX. On Windows
// this assumes that all the file handles for the file to be deleted are
// opened with FLAG_WIN_SHARE_DELETE.
kEnsureImmediateAvailability,
};
// An interface to enumerate files in a directory.
// Indirect descendants are not listed, and directories are not listed.
class FileEnumerator {
public:
virtual ~FileEnumerator() = default;
// Returns the next file in the directory, if any. Returns nullopt if there
// are no further files (including the error case). The path of the
// returned entry should be a full path.
virtual absl::optional<FileEnumerationEntry> Next() = 0;
// Returns true if we've found an error during traversal.
virtual bool HasError() const = 0;
};
virtual ~BackendFileOperations() = default;
// Creates a directory with the given path and returns whether that succeeded.
virtual bool CreateDirectory(const base::FilePath& path) = 0;
// Returns true if the given path exists on the local filesystem.
virtual bool PathExists(const base::FilePath& path) = 0;
// Returns true if the given path exists on the local filesystem and it's a
// directory.
virtual bool DirectoryExists(const base::FilePath& path) = 0;
// Opens a file with the given path and flags. Returns the opened file.
virtual base::File OpenFile(const base::FilePath& path, uint32_t flags) = 0;
// Deletes a file with the given path and returns whether that succeeded.
virtual bool DeleteFile(const base::FilePath& path,
DeleteFileMode mode = DeleteFileMode::kDefault) = 0;
// Renames a file `from_path` to `to_path`. Returns the error information.
virtual bool ReplaceFile(const base::FilePath& from_path,
const base::FilePath& to_path,
base::File::Error* error) = 0;
// Returns information about the given path.
virtual absl::optional<base::File::Info> GetFileInfo(
const base::FilePath& path) = 0;
// Creates an object that can be used to enumerate files in the specified
// directory.
virtual std::unique_ptr<FileEnumerator> EnumerateFiles(
const base::FilePath& path) = 0;
// Deletes the given directory recursively, asynchronously. `callback` will
// called with whether the operation succeeded.
// This is done by:
// 1. Renaming the directory to another directory,
// 2. Calling `callback` with the result, and
// 3. Deleting the directory.
// This means the caller won't know the result of 3.
virtual void CleanupDirectory(const base::FilePath& path,
base::OnceCallback<void(bool)> callback) = 0;
// Unbind this object from the sequence, and returns an
// UnboundBackendFileOperations which can be bound to any sequence. Once
// this method is called, no methods (except for the destructor) on this
// object must not be called.
virtual std::unique_ptr<UnboundBackendFileOperations> Unbind() = 0;
};
// BackendFileOperations which is not yet bound to a sequence.
class UnboundBackendFileOperations {
public:
virtual ~UnboundBackendFileOperations() = default;
// This can be called at most once.
virtual std::unique_ptr<BackendFileOperations> Bind(
scoped_refptr<base::SequencedTaskRunner> task_runner) = 0;
};
// A factory interface that creates BackendFileOperations.
class BackendFileOperationsFactory
: public base::RefCounted<BackendFileOperationsFactory> {
public:
// Creates a BackendFileOperations which is bound to `task_runner`.
virtual std::unique_ptr<BackendFileOperations> Create(
scoped_refptr<base::SequencedTaskRunner> task_runner) = 0;
// Creates an "unbound" BackendFileOperations.
virtual std::unique_ptr<UnboundBackendFileOperations> CreateUnbound() = 0;
protected:
friend class base::RefCounted<BackendFileOperationsFactory>;
virtual ~BackendFileOperationsFactory() = default;
};
// A trivial BackendFileOperations implementation which uses corresponding
// base functions.
class NET_EXPORT TrivialFileOperations final : public BackendFileOperations {
public:
TrivialFileOperations();
~TrivialFileOperations() override;
// BackendFileOperations implementation:
bool CreateDirectory(const base::FilePath& path) override;
bool PathExists(const base::FilePath& path) override;
bool DirectoryExists(const base::FilePath& path) override;
base::File OpenFile(const base::FilePath& path, uint32_t flags) override;
bool DeleteFile(const base::FilePath& path, DeleteFileMode mode) override;
bool ReplaceFile(const base::FilePath& from_path,
const base::FilePath& to_path,
base::File::Error* error) override;
absl::optional<base::File::Info> GetFileInfo(
const base::FilePath& path) override;
std::unique_ptr<FileEnumerator> EnumerateFiles(
const base::FilePath& path) override;
void CleanupDirectory(const base::FilePath& path,
base::OnceCallback<void(bool)> callback) override;
std::unique_ptr<UnboundBackendFileOperations> Unbind() override;
private:
SEQUENCE_CHECKER(sequence_checker_);
#if DCHECK_IS_ON()
bool bound_ = true;
#endif
};
class NET_EXPORT TrivialFileOperationsFactory
: public BackendFileOperationsFactory {
public:
TrivialFileOperationsFactory();
// BackendFileOperationsFactory implementation:
std::unique_ptr<BackendFileOperations> Create(
scoped_refptr<base::SequencedTaskRunner> task_runner) override;
std::unique_ptr<UnboundBackendFileOperations> CreateUnbound() override;
private:
~TrivialFileOperationsFactory() override;
SEQUENCE_CHECKER(sequence_checker_);
};
} // namespace disk_cache
#endif // NET_DISK_CACHE_DISK_CACHE_H_